Anesthetic induction of juveniles of Rhamdia quelen and Ctenopharyngodon idella with Ocimum micranthum essential oil

Abstract

Anesthetics are effective to reduce or minimize stress in handling operations related to fish cultures. Aiming to avoid residual effects of synthetic drugs, several natural agents, such as essential oils (EOs), have been tested. The aim of this study was to determine the optimal concentration of the EO of Ocimum micranthum for induction of anesthesia in juveniles of silver catfish (Rhamdia quelen) and grass carp (Ctenopharyngodon idella). Results demonstrated that the most suitable concentration to sedate silver catfish and carp is 25μL/L, while to anesthetize 200μL/L is more suitable for silver catfish and 100μL/L for grass carp, because these concentrations induce deep anesthesia in less than three min and recovery in less than five min. Analysis of the EO constituents showed methyl chavicol, a compound with carcinogenic potential, as the major component (58.2%). Therefore, the EO of O. micranthum is not recommended for fish anesthesia if the fish are to be used as food.

Essential oils as anaesthetics and sedatives in native Brazilian fish, with a special emphasis on Colossoma macropomum : A review

“…Indeed, fish anaesthetized with this EO did not exhibit alterations in haematological parameters and blood glucose values (Silva, Martins, et al, 2020). In the fish species L. alex- this oil impairs its use, due to its carcinogenic potential (Zeppenfeld et al, 2019).…”

“…The essential oil from Ocimum micranthum was also evaluated for R. quelen , and the concentrations of 25 µl L −1 for sedation and 200 µl L −1 for anaesthesia were determined by Zeppenfeld et al (2019). Regarding anaesthesia, induction to deep anaesthesia (<3 min) and recovery (<5 min) occurred quickly and there was no record of fish mortality.…”

“…Regarding anaesthesia, induction to deep anaesthesia (<3 min) and recovery (<5 min) occurred quickly and there was no record of fish mortality. However, despite the oil from O. micranthum presenting characteristics that are adequate for its recommendation as an alternative anaesthetic for R. quelen , the presence of the estragole compound (methylchavicol) in a large proportion (58.2%) in this oil impairs its use, due to its carcinogenic potential (Zeppenfeld et al, 2019).…”

“…The use of 90 mg L −1 prevented higher levels of plasma glucose and cortisol one hour after handling(Boaventura et al, 2020) Silva et al (2012). reported that the anaesthetic activity of the essential oil of O. gratissimum is related to the benzodiazepine site of the GABA A receptor.The essential oil from Ocimum micranthum was also evaluated for R. quelen, and the concentrations of 25 µl L −1 for sedation and 200 µl L −1 for anaesthesia were determined byZeppenfeld et al (2019). Regarding anaesthesia, induction to deep anaesthesia (<3 min) and recovery (<5 min) occurred quickly and there was no record of fish mortality.…”

The anaesthetic efficacy of Eucalyptus globulus essential oil on silver catfish ( Rhamdia quelen )

“…Therefore, essential oils (EO) are an excellent alternative to replace synthetic products. For this reason, they have recently been widely tested as an anaesthetic for fish (Barbas et al, 2017;Boijink et al, 2016;da Silva et al, 2019;Hajek, 2011;Parodi et al, 2014;Ribeiro et al, 2016;Silva et al, 2012;Weber et al, 2009;Zeppenfeld et al, 2019).…”